in a sense, people with later times are "screwed".
in practice, someone who is pushy and learns the rules well can ALWAYS get what they want. Even filled-up classes, you show up, approach the professor, appear interested and competent, ask if they're willing to sign your Add form, and if not, ask if they wouldn't mind you auditing the class for a few weeks to see how well you get on. After a while, you can wear down even the surliest of professors.
Exception: seminars of under 15 people. Those tend to be close-knit groups and their rosters rather fixed - but those mostly apply to upper-level courses where everyone is off in their own major anyway and there's less competition and more chances to get on a particular favorite professor's good side. For the core classes it pertains to (i.e. lit hum, CC, UW, art hum, music hum, etc), there are dozens of sections every semester and for the single-semester ones (especially art hum and music hum), students routinely add the course with whatever section fits their schedule, they shadow the course for a few weeks to find out about the professor, and then either keep it or drop it (to try again the next semester for a better fit).
It's a game. Doing well in a course isn't a game, it's hard work - but the ins and outs of scheduling and optimization should be approached as a game. Learn to play it well
